Repeated load relaxations of type 316 austenitic stainless steel

Journal Article · Thu Mar 01 00:00:00 EST 1984 · Scr. Metall.; (United States)

DOI:https://doi.org/10.1016/0036-9748(84)90512-X· OSTI ID:6469020

Hannula, S P; Li, C Y

Several experiments have shown that the shape of the load relaxation curve after reloading in a logarithmic stress vs. logarithmic strain rate plot may differ from that after the initial loading. In a recent study Korhonen and Li showed that the apparent kink in a log sigma versus log epsilon plot of the stress relaxation data, after mainly elastic and anelastic loading, is due to change of the deformation mode from an anelasticity dominated one to a plasticity dominated one. According to the state variable model by Hart, the relaxation curve in reloading should overlap with the original one after this transition in the absence of structural changes. Therefore, the crossing of stress relaxation curves after an initial plastic loading and subsequent elastic and anelastic reloadings in commercially pure aluminum at room temperature was accounted for by thermally induced effects. In the same study, consecutive stress relaxation runs were conducted on 316 SS, and no cross-over behavior was observed, which was associated with the lack of thermal effects in 316 SS at room temperature. The results demonstrate that strain aging has an effect on relaxation behavior even at room temperature, the effect being more pronounced at high strains. The phenomena can be accounted for according to a state variable model by modifying the rate constant, which is affected by the amount of mobile dislocations as well as dislocation mobility.

• Research Organization: Department of Materials Science and Engineering, Cornell University, Ithaca, NY
• OSTI ID: 6469020
• Journal Information: Scr. Metall.; (United States), Vol. 18:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
STRESS RELAXATION
STAINLESS STEEL-316
STRAIN AGING
AMBIENT TEMPERATURE
DIAGRAMS
DISLOCATIONS
DYNAMIC LOADS
ELASTICITY
MATHEMATICAL MODELS
PLASTICITY
TEMPERATURE EFFECTS
AGING
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
LINE DEFECTS
MATERIALS
MECHANICAL PROPERTIES
METALS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
RELAXATION
STAINLESS STEELS
STEELS
TENSILE PROPERTIES
360103* - Metals & Alloys- Mechanical Properties